


True Love, At A Price

by FangsScalesSkin



Series: The Succubus Gordon Saga [3]
Category: Half Life VR But The AI Is Self Aware
Genre: (only a little bit), About as much sex as you'd expect from a fic where one character is a succubus, Anal Sex, Biting, Come Eating, Corruption, Cosmic Horror Benrey, Demon Benrey, Demon Deals, Developing Relationship, M/M, Master/Servant, Oral Sex, POV Barney Calhoun, Praise Kink, Putting this in the HLVRAI fandom because Gordon's characterisation is closer to that version, Snowballing, Succubus AU Gordon, This is primarily a Freehoun fic, Transformation
Language: English
Status: Completed
Published: 2020-09-23
Updated: 2020-09-23
Packaged: 2021-03-08 04:35:25
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 8,416
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/26619826
Author URL: https://archiveofourown.org/users/FangsScalesSkin/pseuds/FangsScalesSkin
Summary: If the catch for getting to be with your crush was making a deal with a demon, would you do it?For Barney, the answer to that question is yes.
Relationships: Barney Calhoun/Gordon Freeman, Benrey/Gordon Freeman
Series: The Succubus Gordon Saga [3]
Series URL: https://archiveofourown.org/series/1936456
Comments: 18
Kudos: 135





	True Love, At A Price

**Author's Note:**

> Thank you to everyone who has enabled me in writing this extra self-indulgent AU, and thanks especially to Eggnog for proofreading.  
> It's not really mentioned but Demon Benrey's true name in this is Thulyn-Magyinbinya (Binya for short). Thanks to Auburn for coming up with it!

Gordon had invited Barney back to his place for a few bottles of beer. Now Barney was there in his living room, low key kicking himself on the inside not to read too much into it. They’re just coworkers! Coworkers, hanging out.

So what if Gordon had sucked him off in the shower room a few times, he did that with all of the Black Mesa security team. Which, now that he really thought about it, was kind of odd. Really odd. Why had he never thought about it? He’d never questioned it, simply enjoyed his turn. Could be Gordon’s easy going manner about it, but it was still a weird thing to do at work. He'd have to think about that some more, but not right now, there were more immediate things to worry about.

Like, maybe he wasn’t reading too much into being invited over? But what if he WAS? Barney had a serious crush on Gordon, heck, he basically loved the guy. Now he was sitting on Gordon’s couch with his first beer in his hand hardly touched, vibrating with indecision on whether to make a move. 

"You okay, Barney?"

"Yeah, Doc, I'm just fine." He flashed a nervous smile. They were supposed to be shooting the breeze about work or whatever but Barney was too wound up for it.

Gordon was sitting next to him, almost close enough for their knees to touch. He looked good in slacks and a button down shirt, but heck, he'd probably look good in a potato sack.

"I've been meaning to ask you, actually…" Gordon twirled a strand of hair from his ponytail around a finger almost shyly. "You like me, don't you?"

Uh. Oh. And here Barney thought he was being subtle.

"Don't gotta call me right out like that, Doc. But uh, if I do?" Barney forced his words out in coherent order which was a feat, he was nearly bluescreening. "Would you want to do something about it?"

"Just call me Gordon, Barney." Gordon reached out to lay a hand on his shoulder. Barney was so aware of the contact it nearly burned. "I like you too."

Gordon was leaning in towards him now, and Barney turned to do the same. They were close enough to kiss, but Barney didn't have the nerve to close the gap.

"Gordon…" Barney swallowed hard, he could feel the other man's breath on his face.

"But there's something I need you to do, if you want to be with me." Gordon was watching him intently. Barney felt pinned like a butterfly to a board with that look.

"O-oh. And, uh, what would that be?"

"Just agree to a few terms. I'm sorry Barney, that's the only way we can be together."

This conversation was taking a weird turn. What on earth was Gordon talking about?

"What?" Was this some sort of BDSM thing? An open relationship thing? Something else? What else could there be? Gordon wasn't the kind of person to cheat on a partner as far as Barney knew, so it couldn't be that. "Is this, like, an open relationship thing, because we can talk it over…?"

"No, not really, nothing like that." Gordon smiled like he thought it was funny.

The air around Gordon sort of shimmered or twisted or warped, and Barney closed his eyes, thinking he was seeing things. When he opened them, he was even more convinced there was something wrong with his eyes.

Because there was no FUCKING way the guy Barney had a crush on was a _literal goddamn demon_. No matter how much his eyes wanted to convince him that his nerdy coworker currently had red eyes, fangs, horns, _leathery wings_ and _a tail._

"We can be together _forever_ , Barney, but you have to make a tiny little deal first." Gordon ran a claw down the front of Barney’s shirt. As scary as it was, some part of Barney must have thought it was hot, because he had half a chub all of a sudden. Barney willed his stupid boner to go away and scrambled back to the other side of the couch.

He opened his mouth to ask a ‘what the fuck?’ but instead blurted out the first absolute dumb shit thing that came to his brain.

"I thought you were a theoretical physicist?!"

“I am? Barney, I can be a theoretical physicist _and_ a succubus, one doesn’t preclude the other.” Barney swallowed a hysterical laugh at that; Gordon sounded plain annoyed, like Barney had hurt his professional pride. “You do know what a succubus is, right…?”

“Yep! Pretty sure I do, Gordon!” Barney tried to get his breathing under control so he didn’t start hyperventilating. “You’re not gonna kill me or eat me or anything like that, are you?” Barney’s voice cracked a little at the end, there.

“No, no, nothing like that.” Gordon spoke slow and low, like he was addressing a scared animal. “Why would I? I don’t do that. Plus I like you, Barney. And I thought you liked me too?”

He sounded a little hurt, and Barney thought that was kind of unfair. Gordon was the one who dropped the weirdest possible bombshell on Barney after all.

“No, you don’t get to act all upset about that, that ain’t fair! I just found out that demons exist! And that you’re one of them!”

“Does it change how you feel about me?” Gordon actually sounded sad, and god help him, but that made Barney feel bad for him. 

“Uh. I, uh, I don’t know.” Now that the shock had eased off a little, Barney had a sneaking suspicion that it hadn’t really changed how he felt that much, and that was almost the scariest thing. The scariest thing was his _demon coworker_ he was pretty sure he was still _stupidly in love with,_ sitting on the other side of the couch making sad puppydog eyes at him. It shouldn’t have worked as well as it did, what with the horns and fangs and red eyes and all, but it did.

“I promise I don’t mean you any harm. Really, I don’t. I just want to be with you, keep you safe, and make you feel good.” Gordon sounded so earnest, Barney couldn’t hold on to all of his fear towards him. Sure, he could be lying, but that didn’t fit with what he knew of Gordon. Then again, as far as he’d known, Gordon wasn’t anything other than human…

“Let’s say I believe you,” Barney said, voice shaking a bit, “what kind of deal are you talking about?” Barney could have kicked himself. He was already making concessions. Thing was he _knew_ he had it bad for Gordon. It wasn’t like he could stop crushing on him all of a sudden.

“Make a deal with my master, you become a succubus too, and we can be together as long as you want in any way you want. In every way you want.”

Master? So there was another demon involved. That was more offputting, to be honest.

“Wait. How come the price is me being a demon? Why does your ‘master’ need another one?”

“Oh. Ah, I think… I think he noticed I was lonely.” Gordon looked away from him and down at his own feet, his face going a bit pink. “You won’t have to do anything you don’t want to, I swear.”

“Gee, that’s generous of him. I’m kind of suspicious of that, I won’t lie.”

“Mmhm. Look, I won’t pressure you to accept, but do you want to at least sit together while you think it over?” Gordon spoke softly, looking at him from beneath lowered eyelashes, holding out a hand, palm up. 

Barney took it.

Barney half expected something dramatic to happen, like a big demon to appear in a cloud of smoke and shout “haha, got you, sucker” but no, they were simply holding hands. Gordon pulled Barney over to his side of the couch until they were sitting side by side, and leaned against him slightly. They were still holding hands.

Gordon’s hand was warm, not too hot or too cold like Barney might have expected from the whole supernatural being thing. He looked down at how their hands fit together, and thought about how it might be to have this all the time, and more. Gordon had wicked looking claws in this form, but he was careful with them as he ran a thumb back and forth over the back of Barney’s hand.

Barney’s heart was beating double time, but he didn’t think it was from being afraid anymore. More from being next to someone he loved. Did Gordon know how much Barney cared for him, that he was sitting next to him, seriously considering what Gordon had said despite all that went with it? Barney hoped he did. He could feel his determination not to make any rash decisions falling more and more to pieces every time he looked in the other man’s eyes. It wasn’t long until it had fallen apart entirely.

“Fuck it, yes. Yes, I accept. Hope you weren’t lyin’, Gordon, or you’ll break my damned heart.”

Next thing Barney knew, he was being pulled into an all-encompassing embrace, Gordon’s wings and all wrapping around him. “I hoped you would, but - I was afraid, too.” Gordon kissed along his jawline and whoops, Barney’s sadly neglected half-boner took an interest in the proceedings. He honestly wanted to melt into the embrace, turn off his thoughts and just let himself enjoy being close like this, before whatever spooky shit might happen next.

“So good of you to decide to join us,” a monotone voice intoned from behind Barney.

Barney jolted in place. He went to turn his head, but Gordon grabbed his face firmly but gently, holding him still.

“That’s just my master - our master, now. Don’t worry, he’ll look after us. He’s only here to make our deal official. There’s no need to be afraid, just relax, and I’ll make you feel good,” Gordon murmured, and stroked his cheek tenderly, kissed his lips.

“Kind of can’t turn off the ‘being afraid’ bit just like that, darlin’, but I’ll try.” Barney ran his hands over Gordon’s chest, then went back and started unbuttoning his shirt, desperate to reveal Gordon’s skin and get to touch him at last. He’d always been buttoned up any time Barney saw him, no matter what he was doing. While Barney was talking, Gordon ghosted a breath along his neck and started to lay kisses there as well, sucking the skin a little every now and then. It was electric, and Barney felt himself get fully hard just from that and from knowing Gordon was his. “I want you so bad. Have for a real long time.”

“I do too. What do you want, Barney? Come on, tell me. I’ll give you anything you want.” Gordon had a wild, desperate look in his eyes at odds with how gently he touched him.

“I, uh… How’s about you ride me? Might have been thinking about it before.”

“Oh, I can do that, sweetheart.”

Gordon went to open Barney’s fly but in his rush, ended up tearing Barney pants apart with his claws instead. Barney swallowed hard because that was a close call. Didn’t make his hard-on go down any, though. He laughed nervously.

“Ooops, sorry Barney, I got a bit carried away.”

“It’s fine! Just careful with those, I nearly lost my damn dick.”

“Sorry, sorry.” Gordon gave him a peck on the cheek to apologise, and Barney’s heart had to be soft as butter because he forgave him already.

“How about you make it up to me by ridin’ me hard?” 

“Can do,” Gordon grinned. He stood up and took off his slacks, somehow making it look sexy and effortless and not accidentally shredding them to bits. Then he crawled right on back to Barney’s lap, kneeling up and positioning himself over Barney’s cock.

“Wait, wait, don’t you need -” Prep, Barney was about to say, but Gordon was already working himself down onto Barney’s dick, going all the way and bottoming out as if it was effortless. Barney gasped like all the air had been squeezed right on out of him.

Gordon took that opportunity to lean in and kiss him with tongue, teasingly sliding the tip into his mouth first and then the rest when Barney nodded. There was a lot more of it than Barney expected, his mouth felt _full_ as Gordon made out with him, and as he started to thrust on up into Gordon, he couldn’t help letting out a few muffled whimpers at how intense it was all at once.

Kissing Gordon was like nothing else. It was beyond passionate. It felt like being claimed and devoured, with Gordon’s long tongue filling his mouth. Gordon kept on kissing while Barney fucked him. The little noises Gordon made when Barney moved were driving Barney wild, but eventually he had to break the kiss to breathe. Both of them were flushed. It was damn nice to see Gordon losing his composure, demon or not.

“Going to - going to make you feel,” Gordon was panting, and when Barney thrust up into him, he gasped, “s-so good.”

“Already do.” It was true. Barney had no idea how he was going to last.

“Hhh. I mean. All the time.” Those bright red eyes looked at him earnestly, even as Gordon rocked back and forth on his dick. Barney watched fascinated as Gordon’s batlike wings fluttered when he started to speed up.

“Sweetheart.” It was hard to speak with Gordon trying his utmost to make him feel good. It was a testament to how completely gone on Gordon he was that Barney had agreed to the deal he offered, but fuck if being a real life sex demon didn’t make the other man incredible in the bedroom. It might be his horny brain talking, but it didn’t look like there were really that many drawbacks so far especially if he got to fuck Gordon like this more often.

Barney held on to Gordon’s hips for dear life as Gordon lifted himself up and dropped back down onto Barney’s dick repeatedly, moaning in a way that Barney felt right the way down his spine.

He was caught by surprise when Gordon bottomed out again, thighs quivering, and arched his back and came right on both their stomachs. Gordon’s eyes fluttered open and closed and he moaned, sounding as if it was the best he’d ever felt. Barney tried to frame that image in his mind for later, because he’d sure as hell be jerking off to it later. 

Barney stopped moving almost entirely, difficult as it was when he hadn’t gotten off yet. He didn’t want to keep going and overstimulate Gordon. Gordon fluttered his wings again, and Benrey noticed Gordon’s tail slowly curling and uncurling on the cushion beside him. It was kind of cute, actually, the way it moved - like a cat’s tail or something.

Gordon opened his eyes but still looked pretty fucked out. He looked up over Barney’s shoulder at whatever was behind him and - oh yeah, there was that demon presence thing looming behind him. Gordon’s so-called ‘master’. Barney would have preferred not to have remembered that, it kind of scared him. 

Before he could turn around and get a glimpse of it, Gordon took Barney’s face between his hands again. Gordon didn’t want to let him see for some reason and it was kind of frustrating.

“Close your eyes.” Gordon ran clawed fingers through Barney’s fringe, so gentle and careful for how wicked the points looked. “You trust me, don’t you?”

“Yeah, yeah I do.” Even if it annoyed him a little not to be allowed look - he was literally placing himself body and soul in Gordon’s hands. He closed his eyes. “I’m gonna want to look sometime. I think I deserve to see.”

“You do, just... Not right now, Barney. Please just trust me.” Gordon reached up to Barney’s shirt collar, untied his tie, and then tied it around his head instead, smoothing the fabric out. He leaned in, and Barney held his breath as Gordon pressed a kiss over one eye and then the other.

Barney felt around and grabbed Gordon’s hand, mindful of his claws, and laced their fingers together.

“Hope it won’t get me in trouble, but. Yeah. I do. I trust you, Gordon.”

“You won’t regret it. I promise. I’ll look after you, make you feel better than you _ever_ have before.” Gordon kissed him again, nibbling oh so lightly on Barney’s lower lip. With the blindfold on, that little bit of stimulation stood out much more. 

Barney’s hips bucked slightly when Gordon started to move again. It was more intense after stopping for as long as he had. Gordon sped up, grinding his hips down on Barney’s cock. It was a bit hard to tell when he couldn’t see, but at the same time as Barney was fucking Gordon, Gordon had hooked his chin over Barney’s shoulder and was doing _something_ with his mouth that sounded incredibly obscene. There were little wet noises happening right next to Barney’s ear, and as confused as he was by it, the sounds turned him on that bit more as well. It sounded like maybe Gordon was sucking someone off - his mysterious master that he wouldn’t let Barney see?

He’d be lying if he said that Gordon’s muffled little mewls of pleasure didn’t go straight to his head. Like, wow, Barney already knew it, but Gordon _really_ liked sucking cock.

There was a rumbling sigh from behind Barney, deep and loud enough to vibrate through his bones a little. The voice from before boomed out a “well done, pet” uncomfortably loudly, considering he was right behind Barney. Gordon just moaned in response, holding on to Barney and shivering a little. Barney stroked Gordon’s back soothingly. 

Gordon nuzzled his face against Barney’s cheek. He pressed their mouths together, the tip of his tongue gently parting Barney’s lips. Barney opened for him, remembering the earlier kiss. Like before, the way Gordon kissed was overwhelming, leaving Barney to gasp around Gordon’s tongue.

Unlike before, there was a strange sweet taste to the kiss, and Gordon tipped Barney’s head back with one hand, letting something flow down from his tongue to Barney’s mouth. Barney swallowed automatically, and the stuff burned slightly going down his throat. He felt warmer too, and sensitive where Gordon’s body rubbed against his, and only got warmer and more sensitive when he swallowed more. Barney let out a muffled moan despite himself. 

What _was_ that? Some weird aphrodisiac? It was really effective whatever it was. He couldn’t help how he rocked against Gordon as the kiss went on, wanting to fuck up into him but unable to get leverage with the position they were in.

Barney tried to chase Gordon’s mouth when Gordon pulled away from the kiss. It was too good, he needed more.

Lucky for him, after another little interval of Gordon taking time-out to noisily suck a dick over Barney’s own shoulder, Gordon’s lips were back against his. His lust-fogged brain had managed to figure out by then that the stuff Gordon was kissing into his mouth was cum, regardless of how odd it tasted. The little spike of pleasure it gave him stopped him from feeling too bothered over snowballing cum from Gordon’s weird patron. It tasted good, and when he swallowed, it felt good. He wanted more. He was too horny to think it was strange just _how badly_ he wanted more. 

Barney kissed Gordon back more aggressively, and he felt as well as heard Gordon purr. Gordon’s nails traced lightly and carefully over Barney’s scalp and it was wonderful. He rutted into Gordon’s ass and came hard, the sounds he made swallowed by the other man.

Barney could hardly bring himself to break the kiss, but he had to breathe eventually. He dropped his head to Gordon’s shoulder and panted harshly. Holy fuck. Despite coming, he still felt kind of sensitive.

He just wanted to stay there, holding Gordon, and drift on how nice he felt. Post-orgasm cuddling his crush sounded really nice right now. Unfortunately he was jolted out of relaxing when something warm and slimy traced over his shoulders. Was that a goddamn tentacle?!

"Betcha liked your first taste of the great Binya's demonic essence. Sure looked like it anyway." 

Barney tensed up. Was this 'Binya' going to ask him for something? Now he wasn't as loved up - the tentacle touching his back had startled him out of it - Barney was waiting for the catch.

"I'm gonna leave you two lovebirds to cuddle. When you want more you gotta come beg me, Barney boy. Be seeing ya." The being laughed, strange harmonics in his voice.

The overbearing presence behind Barney vanished all of a sudden. Well… Okay. That happened. At least Gordon was still here, it wasn't a trick where he'd vanish as soon as Barney had sealed his own fate. Which was a little dramatic but he was kind of shaken by what the entity had said before leaving, so cut him some slack.

"That can come off now." Barney felt hands undo the makeshift blindfold. He blinked as it was removed. "There you are."

Gordon smiled and the affection in his ruby red eyes was deep enough that Barney could just fall right into them and never get back out.

-

Barney propped himself up on his elbow to look at Gordon. He had been happy to move to the bedroom to cuddle after sex, but something was bothering him.

"No offence, Doc, but I don't wanna submit to no demonic master. And I'm definitely not gonna go begging him to come down my throat. Just wanna be with you." 

Gordon laughed. "No offence taken. You will, though. Want to.”

“You sound mighty sure of yourself.”

“Mmhm.” Gordon gave him a small, knowing smile. It made Barney shiver a little. He trusted Gordon not to get him into harm but it was just kind of spooky. He was gone now, but Barney hadn’t even seen the guy, or the demon, or whatever he was. Who knows what he looked like in full. All Barney knew was that he'd seemed to have literal honest to goodness _tentacles_.

Gordon reached out to stroke Barney’s hair. He must have seen a trace of worry in Barney's expression. "You won't regret it. Plus, I get to be with you now."

"I love ya, Doc. I just hope you're right." Barney made it sound like it was kind of a throwaway comment on purpose, saying he loved him, but the thing was Barney meant it.

Gordon went a bit red at it anyhow. It was kind of adorable. Even with Gordon's face framed by curving horns, an unavoidable reminder of what he was.

"O-oh. I, um." Gordon blushed deeper and looked away from Barney, biting that pouty lower lip of his. He looked back at Barney again, seeming flustered. "I love you too, I think?"

Add 'flustering a literal sex demon' to Barney's resume. He grinned. "I got plenty time to turn that 'I think' to an 'I know'. How's about a date this weekend?" That was doing things kind of backwards, but fuck it. He had a chance to romance Gordon, he was going to take it.

"I'd like that." Gordon snuggled back in close, wrapping his tail around Barney's thigh and stretching out a wing to cover them both like a blanket. It was unfair how sweet he was, for a demon. Barney would have to ask sometime how he'd ended up that way.

-

So was Barney a demon now or not? He was a bit confused. He didn't seem to have the whole horns and tail and wings going on that Gordon did. As far as he could tell from looking in the mirror, the only difference in his appearance was his ears were gone a little pointy and his eyes looked a bit funny. Like there was something up with the shape of his pupils, and his irises were yellowing. It wasn't _nothing_ but it was nowhere near as dramatic as he expected.

That and he found he was kind of sensitive to touch. Enough that he shivered a little while pulling on his work clothes in the morning, keenly aware of how the fabric brushed against his skin. That’d take some getting used to.

He met Gordon at the tram stop to work. Gordon linked their arms together, looking totally normal - green eyes, and no horns or wings or tail or claws - and sat next to him the whole tram journey, talking enthusiastically about some experiment his team were running. It was honestly pretty reassuring. Sure, Gordon had turned out to be a demon, but he was still the big physics nerd Barney had gotten to know and love; that hadn't been an act just to draw him in.

It was plain adorable how red Gordon got when Barney caught him staring with a little smile on his face. The man had no hesitation around sex but got so embarrassed about having a crush. It made Barney want to tease him a little, but he didn't know how Gordon felt about romantic PDA. He'd have to ask now they were dating and/or bound together in a demonic pact.

They parted ways with a promise to meet back at Gordon's office for lunch. Barney honestly wasn't sure if Gordon meant actual lunch or having sex but he brought his sandwiches in case.

-

Turned out that Gordon had meant actual lunch, although for Gordon that consisted of a protein shake and a chocolate bar from one of the vending machines. Well, at least that confirmed he could still eat regular food.

"So, Doc. How come you're a demon anyway? I get the feeling you weren't always one, unless demons make a habit of going to MIT."

"Oh, god, it's kind of embarrassing really. When I was working on my doctorate, I got denied grant funding, and I got pretty desperate to avoid taking out a loan. So, uh, I was really sleep deprived one evening and decided I might as well try summoning a demon. Couldn't hurt, right? Aaand it actually worked."

"You're shitting me."

"Nope! Traded my body and soul into eternal demonic servitude to pay for those two fancy letters in front of my name." Gordon smiled wryly, rolling his eyes like it was a wacky thing that could happen to anyone. "If you're wondering, I don't regret it. Pretty good deal, really."

"The demon paid for you to finish college."

"Yep. You wouldn't believe how many dicks I sucked in MIT." Gordon punctuated that statement with a particularly noisy suck on the straw of his protein shake, and Barney had to shake his head and laugh.

"You're really something else, you know that? In a good way."

Gordon reddened a little. Before Barney could get distracted by his surprising cuteness, he had another question to ask.

"One other thing. Am I a demon now? I don't feel much different, heck I don't look that different either."

"Hmm. Not really, yet. Just a bit."

"Well how come?"

"You, uh." Gordon tapped his nails on the plastic of the protein shake container. "Haven't consumed enough of our master's essence yet. By which I mean his cum, or other fluids."

"Uhhh. Right." Hearing Gordon say that with a straight face was _absolutely bizarre._ Barney would think it was a joke if he didn't know he was serious. That and he didn't want to be rude and contradict Gordon when he said 'our master', Barney had more manners than that, but hearing it was super weird too on top of the rest. "Not sure I wanna do that."

"No?" Gordon tilted his head to the side slightly, and Barney swore he saw his eyes flash red for a second. "I thought you wanted to be with me? I want that too, but I can't unless you're a demon…"

"I do, darlin', it's just a lot to take in. Gotta give me time, you know?"

"Alright, I understand. Take your time." Gordon gave him a little smile. "I'll be waiting, though."

Barney smiled nervously back at him.

Gordon unwrapped his chocolate bar and bit into it, eating with a thoughtful look on his face.

"If it's about not wanting to interact with our master yet, we can always snowball some more." 

"Huh." Lord help him, but Barney was considering it. He _had_ enjoyed that part the last time. "I'll think it over. God, if anyone overheard this conversation, they'd think we'd lost it."

Gordon gave an amused snort. "Yeah, that's for sure."

The rest of their lunchbreak went on more normally, chatting about work and inconsequential things. It was nice. At the end, Barney gave Gordon a little kiss on the cheek just to see him smile and get all blushy again.

-

Work was boring, but it was still a super weird week for Barney. He was floating on that new relationship high, getting to be closer with Gordon, hold his hand, give him little chaste kisses, all that good stuff. He was also fretting over the thought that if he wanted to get intimate with his boyfriend beyond a quick bj in the shower room, he'd have to let himself be turned into a demon.

He'd said yes before _but_ he'd also been really horny and starstruck at the idea of being with his crush for real. This in-between period was like a second chance if he really wanted to change his mind. He could stay mostly human, leave things like that, apologise to Gordon and nurse his own heartbreak.

The thing was, though, he kind of didn't want to. Not only was he pretty in love with Gordon, but last time had felt incredible.

He found himself zoning out while standing around at work, thinking of those kisses from before in particular. How it'd tasted. How it'd felt. He was nowhere near ready to call some demon 'master', but he wanted to kiss Gordon like that again, touch and be touched in turn, feel the burn of the demon's essence as he swallowed it and lit his insides up with pleasure. Fuck, it would be amazing.

Barney's willpower must be pretty weak, because he'd had more than one inconvenient boner while fantasising about it. He'd had to dash off to the bathroom with some excuse about a sensitive stomach and jerk off as quietly as he could in one of the stalls. He ended up imagining how he could bring Gordon with him, let the other man suck him off right then and there.

After he'd come into his hand and hastily wiped the most of it off and thrown the tissue into the toilet and flushed it, so he could wash his hands without being obvious about what he'd been doing, Barney had a realisation. Nobody ever seemed to notice or remark when Gordon did something overtly sexual like that even in a venue like the security team locker room. Barney hadn't noticed either until he really thought about it. Was that a demon thing? Making it so nobody noticed anything was out of the ordinary? Kind of handy if it was, really.

-

Friday rolled around and with it, Barney's date night with Gordon. He'd chosen a movie date with some takeout over at his place, and he was fluttery with anticipation and nerves, both of the regular "oh god I hope this date goes okay" kind and the "oh god I am totally going to let myself get turned into a demon further" kind.

They had dinner, an Indian takeaway, and Barney tucked into a biryani enthusiastically despite his nerves while Gordon ate a jalfrezi and seemed to enjoy it. That helped Barney let go of some of the tension he'd been holding. It would be a crying shame not to be able to enjoy food anymore. Apparently that was vampires, though, and not succubi who couldn't eat regular food. (Barney had to wonder if vampires were real, or if it was just demons. He wasn’t sure if he wanted vampires to be real. Aliens would be pretty cool though.)

For the movie he'd chosen a big budget sci-fi, something he was relatively sure they'd both enjoy, and he was proven right. Gordon cuddled up to him, criticising the physics in the movie until Barney threw popcorn in his face and made them both laugh.

The movie ended and cuddling turned into heavy petting and making out. Gordon was straddling his hips and kissing him hungrily, and it was all very nice except he didn’t go any further. Did he want Barney to initiate having sex…? Gordon did say to take his time. Maybe he was holding back and trying to be considerate.

“Hey, hey darlin’. How about we move this to the bedroom?”

"Whatever you want." He had this knowing little twinkle in his eyes and, okay, that was kind of hot in and of itself. He took his jacket off and threw it on the couch. "Mind if I get a bit more comfortable?"

"No, go ahead."

Gordon stretched out and sighed, and in the blink of an eye his demonic features were back. He flapped his wings a few times. "Feels nice to stretch those out."

"You look good both ways." 

"Thanks Barney, you're a sweet guy." Gordon softly kissed him on the cheek and then stood up before either of them could turn one kiss into another makeout session, and held out his hand. "Lead the way."

Once they were in Barney's room, Gordon got down on his knees before Barney could do anything else.

"Wanna suck your cock, for old times' sake." Gordon had a distinctly hungry look in his eye and if Barney hadn't been hard already, that would be enough to do it for him.

"Of course, darlin', anything you want." Barney undid his belt and kicked trousers and all off, leaving himself in only his shirt and socks. "What do you mean by old times' sake though?"

"Might taste different after you change." Gordon wasted no time getting Barney's cock in hand and licking right along it. "Not sure if it will, but. Be fun to compare. Nice to get to give you personal attention too. I always had to rush before during lunch times."

With that, he slid Barney's cock into his mouth. He made a pleased little humming noise, closing his eyes and bobbing his head up and down, hollowing out his cheeks to apply the kind of suction that made Barney's legs go a little weak. Barney reached out to pat Gordon's head, and he was struck by how Gordon smiled around the cock in his mouth.

"D-does it really taste _that_ good," Barney panted out.

Gordon opened his eyes and looked up at him, seeming kind of dazed. He pulled off of Barney's cock with a little pop. "Yeah. Feature of, uh. Feature of succubus biology I think." He took Barney's cock back in his mouth, going all the way until his lips were almost pressed to Barney's stomach and bottoming out. Holy fuck.

Gordon swallowed around him and _purred,_ deep vibrations that Barney could feel surrounding his cock. Barney grabbed onto Gordon's horns and let himself facefuck Gordon, and Gordon purred all the more loudly, reassuring Barney that Gordon was enjoying it.

There was no way Barney could last. Gordon's mouth was just perfect, and his technique made Barney's eyes roll back. He came abruptly, spilling his load right down Gordon's throat. Gordon made a pleased little noise, swallowing around him. He kept swallowing until Barney was well and truly finished.

Gordon pulled off and let out a blissful sigh, a truly relaxed look on his face. "Thanks babe, I really enjoyed that," he said, sounding only a little hoarse.

"Babe?" Barney parroted back, still in a daze.

"You don't like it?" Gordon frowned a little. "I can use something else… I thought it was cute though."

"No, no, babe is fine. I like it." Barney ruffled Gordon's hair, pleased when Gordon let out another happy little sigh.

"What do you want to do next?"

"Well, earlier on in the week you mentioned snowballing, so maybe… More of that. And then you could fuck me?" His voice got a little high at the end from nerves. 

Gordon grinned wickedly at him, standing up and pushing Barney back onto the bed. Thank goodness he seemed to understand what Barney was getting at without any further explanation, because it was kind of embarrassing and kind of scary to admit that yes, he wanted to do this whole thing.

"Lie back, darling, and close your eyes. I don't want you to hurt yourself by looking at our master before you're ready."

Barney scrambled into place, lying down and placing his head on the pillow, bunching up his shirt in his hands and deliberately breathing deep to calm himself.

Gordon sat beside him, cleared his throat, and called out. " **Master?** "

It felt like the air pressure in the room increased abruptly. Maybe because there was suddenly something a lot bigger in there? Barney didn't know, he wasn't the one here who was a scientist.

" **Yes, pet? You called for me.** " Barney flinched at the loud voice, wanting almost to call out and tell the demon to stop being so damn _loud_.

"Barney said he wants more."

"Hella." Barney could practically hear the smug grin. "Be nice and polite, 'Barney', and you can have it. Won't even make you get down on your knees to beg, I'm cool like that."

"Um, please?" 

"Good boy, ten outta ten, top marks for a beginner." A strange, vaguely tingly feeling went through him at the words - kind of like ASMR or something? - and Barney felt his cheeks grow hot. The demon's speech patterns were pretty weird for a fuck knows how old extra-dimensional being, but apparently Barney was into that now that he was less completely freaked out by the whole situation. Who knew?

Barney lay there and did more deep breathing and listened for the tell-tale slick sounds of Gordon giving oral.

Sooner than he expected, the bed shifted under Gordon's weight, and Barney felt him kneeling over him. A clawed thumb brushed his lower lip and Barney opened his mouth, heart racing in what was mostly anticipation mixed with a little fear of what this was going to do to him. Calling it a poisoned kiss was overdramatic but Barney's stupid brain wouldn't shut up in the few seconds before Gordon pressed their lips together.

As soon as he tasted the strange, sweet liquid again his thoughts shut right up about everything else. It was slicker this time, more like a mystery fluid of some sort than cum, which was odd - like, what was that? - but everything else was the same, down to the way it burned slightly when Barney swallowed, and the way his body heated up when it started having an effect.

Barney made a muffled noise and grabbed Gordon's horns to crush their lips together more. Gordon purred, his tongue curling around Barney's. Barney felt a weird uncomfortable pressure in his head like something trying to get out, but everything else felt good enough that he didn't care. He pressed his tongue into Gordon's mouth to chase for any more of what he was desperate for. He outright whined when Gordon broke the kiss.

"Patience, darling." Gordon placed a finger on Barney's lips to shush him. Barney opened his mouth, and dragged Gordon's finger in with his tongue to suck on it. He wanted something to occupy his mouth, keep his mind quiet while he waited for Gordon.

Next thing he knew, Gordon was pulling his finger out of Barney’s mouth and catching hold of Barney’s jaw to hold him still. Then they were kissing again, and Barney let Gordon in eagerly, welcoming the overwhelming sensation of Gordon’s tongue filling his mouth and the sweet burn of the demonic fluids he was swallowing down. Anything that felt this good had to be worth it. The pressure in his head intensified, localised around two points a little ways back from his forehead, and Barney whimpered at the discomfort. Gordon stroked his cheek and made an apologetic noise. 

All at once the pressure broke. Barney felt like his skull was being _stretched_ , but somehow it wasn’t painful. Heck, his cock was hard again and everything, which he became hyper-aware of when Gordon stopped kissing him and sat back on his thighs.

“Oh, darling, they suit you so well.”

“What do?” Barney was kind of out of it, hot all over and sensitive to every little touch, his cock leaking pre a little where it pressed against his stomach, so sue him if he didn’t know what Gordon was talking about.

“Your new horns. So handsome. You should see yourself.”

Oh. Barney reached up to feel at either side of his head, and sure enough. Curling back from the sides of his head were two spirally horns, like a ram’s. That was official then, huh. Barney was a demon now.

Somehow he thought it would change him in ways other than the physical, but he felt like the same old Barney Calhoun, just with horns now. 

He let out a deep, relieved breath, opening his eyes to look up at Gordon and deliberately ignoring anything else in the room. Gordon’s leathery, dark wings were extended anyway, blocking his view of the rest of the room. Whether that was intentional or not didn’t matter.

Gordon had a small smile on his lips as he caught Barney’s gaze, and he ran his fingers along one of Barney’s horns. It didn’t really feel like much - the best comparison was like something jostling his nails or teeth, only sensitive where it connected with the rest of his body. 

“We can be together properly now. Really and truly.” 

“That’s all I want, darlin’.” 

They stared at each other in absolutely the soppiest way imaginable until a thought came to Gordon, his smile curling into a grin. 

“I thought you wanted to be fucked, too.”

“Now that practically goes without saying.” Barney grinned back at him. “I know you want a piece of this too, so don’t go getting too clever. Lube’s in the nightstand.”

Gordon reached over, opened the drawer and swiped it, handing it to Barney. Barney put a generous amount on his fingers - thankful he didn’t have to deal with having claws yet - and worked one and then two fingers into himself. Weird, but it went much easier than usual. Heck, he was able to fit three without a bother, it was mostly a matter of slicking things up back there rather than stretching.

“We’re good to go.” Barney gave two thumbs up.

“Mmm. Are you ready to scream for me, babe?” Gordon lined himself up to slide into Barney, grinning wider to show off his fangs.

Fuck but that was hot. Gordon being all assertive. Barney might have needed to sit down if he wasn’t already lying on his back.

“Y-yeah, I think so.” Barney gripped the bedsheets while Gordon started fucking right on into him. He slid home easily, and Barney arched back at being filled so quickly. Wow. Wow wow wow.

Maybe Barney was being sappy and horny at the same time, but it felt as if they were made to be together. Gordon fit inside him so well. Then Gordon started to move and Barney was sure of it. They were meant to be.

He held on to Gordon’s shoulders as Gordon sped up until Barney was moaning openly. Gordon kept hitting his prostate just how Barney liked it, and Barney knew he got really vocal from prostate stim anyway. If Gordon wanted him to scream, Barney wasn’t going to have to fake it.

“Hey, hey darlin’. Ohhh fucking god damn.” Gordon had thrust in again. It was hard to hold on to a single thought in the face of that. “H-How’s about you, you bite me up a lil bit?” Being marked up by his boyfriend sounded good right about then. Being really _claimed_ physically. Barney took a hand away from Gordon’s shoulder to jerk himself off to the thought.

“Ah - ah, anything you want. Want you to, to feel good.” Gordon nuzzled into his shoulder, leaving little kisses, and then bit down hard. Barney shouted a ‘ _FUCK_ ’ and jerked in place below him. Gordon let go, and licked the bite mark to soothe it a little. He did it again, and again, leaving a whole trail of bloody bites.

“Gordon, Gordon, Gordon, love. Gggguhh.” Barney fucked into his own fist and tried to manage words. Tell Gordon that he did, he made Barney feel so good. “ _Gordon,_ ” he wailed, coming into his hand.

Barney felt like he’d whited out, his head full of static as he rode his orgasm while Gordon fucked him right through it. When the aftershocks faded, he lay there in a daze. All he could do was pat at Gordon’s hair and mumble that he did a good job when Gordon came in his ass. Barney felt the absence strongly when Gordon pulled out at last. Gordon lay right down on top of him and Barney threw his arms around Gordon’s waist, mindful of his wings, and closed his eyes for a few moments.

-

"What's cookin', good lookin'?" Barney felt a slimy tendril of some sort curl under his chin and tip his head up. He blinked, and then squinted up at the source of the voice.

There was a pile of TENTACLES and EYES looking down at him and Barney had _never_ been startled out of an afterglow that quickly. What the shit. That was the DEMON? The thing was alien looking and not in a fun way. More a make your head hurt way. Barney let out a whimper.

"Calm down." Barney's muscles relaxed without any input on his part and he grew quiet. "Good pet."

Barney gasped, a long rolling shiver running down his spine. It was like something had reached in and lit up the pleasure centres of his brain directly. It was way stronger than the few little tingles he’d experienced earlier, he could barely keep his eyes from slipping shut to focus on it alone.

"Ooh, you felt that one, didn't ya? I'll have you calling me Master in no time."

"What?" Barney had trouble replying. His mind felt like it had melted after a couple of orgasms and now this. He couldn’t manage any panic anymore.

"Don't worry your pretty little head about it. I've got stuff to do, I’ll see ya around." The demon wiggled his claws in the air at Barney in a sort of wave. His many, many eyes turned to Gordon, who had sat up on his knees and was watching him intently. "Goooood boooooy. Real pro strats tonight. My little succubus is so well behaved, isn't he? Yes he is. Yes he is. Gonna give you a nice reward later for being so good."

The demon ruffled Gordon's hair. That done, he vanished into thin air. Barney looked at Gordon to see how that torrent of praise had affected him, and _wow_. Gordon's eyes were fluttering rapidly before rolling back, and he didn't seem entirely conscious of his surroundings as he arched his back and nearly fell right off the side of the bed. Barney caught him in time, and rearranged him on the bed while Gordon twitched in his arms and came untouched. His mouth was hanging open and he looked utterly wrecked.

Barney stroked Gordon's hair and waited for him to finish. "That really has a powerful effect on you, huh."

“Mhhhhm.” Well, he was able to hear Barney and respond in some kind of way, that was a good sign.

“How about we just cuddle here a while until you’re able to talk again, sweetheart?”

Gordon nodded and laid his head on Barney’s chest. Barney held him, giving a comforting little squeeze every now and then. 

It still took him a bunch of time until he spoke again.

“Should have a look in a mirror. Want to make sure I’m here the first time you see your new features. Make sure I can tell you how I see you.” 

That was so sweet that Barney found himself blushing. Real melt your heart stuff. How’d he get so lucky? Aside from the, uh, demon deal bit.

"Alright, once we can both stand up again."

Gordon let out a small laugh.

They managed to stagger together to the bathroom. Barney felt a twinge of fear as he reached out for the light switch. It was one thing to touch his new horns, another to see them.

"It's ok, Barney," Gordon said, wrapping his arms around Barney's waist from behind and resting his chin on one shoulder. "You're still you. You just have a few enhancements is all."

"Enhancements, sure." Barney switched on the light and looked at himself in the mirror. He did his best not to recoil. He had horns, yes, like a sheep or a goat, but his ears were even longer than before, the backs of them covered in fuzzy black hair. His ears flicked back automatically as he looked, able to swivel a bit now, and that added to his expression of dismay. And his eyes - his irises were yellow, and the pupils slitted horizontally like a goat's.

"That's, uh, that's going to take some getting used to."

"I bet. I think you look handsome though." Gordon gave him a little squeeze. "My handsome goat demon."

"Least goats aren't too bad. Stubborn, scrappy little bastards. Like me. I can live with looking like one of those."

Gordon kissed and nuzzled the side of his neck, and Barney was suddenly keenly aware of the bitemarks from earlier. Now those, _those_ looked good. Whatever about being owned by a huge, spooky tentacle demon according to the terms of his deal, it was Gordon who _really_ owned Barney. He liked that. It made him feel cherished.

"Let me show you how to put on your human disguise, babe."

Human disguise, huh? That's right, Barney wasn't human. Not anymore.

**Author's Note:**

> I'd love to know if you enjoyed this fic! 
> 
> I might be writing another chapter or some oneshots set in this AU again sometime, after finishing other WIPs. Barney isn't entirely finished becoming a demon yet, after all.

**Works inspired by this one:**

  * [Summoning 101](https://archiveofourown.org/works/26730070) by [NiamhofTirnanOg](https://archiveofourown.org/users/NiamhofTirnanOg/pseuds/NiamhofTirnanOg)




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